This application is a reissue application of U.S. Pat. No. 8,407,927, titled Locking Adjustment Dial Mechanism For Riflescope (U.S. patent application Ser. No. 13/331,599, filed Dec. 20, 2011, which is a continuation-in-part of my co-pending U.S. patent application Ser. No. 12/363,658, titled Riflescope High Speed Adjusting Elevation Assembly, filed Jan. 30, 2009 and claiming priority to U.S. provisional patent application Ser. No. 61/063,265, filed on Jan. 31, 2008, and Ser. No. 61/144,400, filed on Jan. 13, 2009), which is hereby incorporated by reference herein in its entirety.
1. Technical Field
This invention pertains to riflescopes and more particularly to riflescopes with elevation and/or windage adjustment knobs that can be releasably locked at a preselected “zero” position.
2. Description of the Related Art
Riflescopes typically include elevation adjustments that enable the shooter to shoot accurately at different target distances by turning the elevation adjustment mounted on the top of the riflescope. When the elevation adjustment is rotated, the riflescope's elevation changes from the scope's zero point. Conventional elevation adjustments on a riflescope have preset “click” values which determine the amount of elevation change when the adjustment is rotated one click or to a pre-determined mark on the adjustment. Most elevation adjustment knobs have a click value of ¼, ½, or 1 minute of angle (MOA) or milliradian or some other measurement unit.
The smaller the click value, the greater number of rotations must be made to the elevation adjustment to adjust to different target distances. This can create a slow and confusing situation for the shooter because the dial position must be counted and does not reflect the actual scope adjustment setting, thereby slowing engagement time with the target. If the elevation adjustment has relatively small MOA (or milliradian) click values, the total amount of elevation movement per rotation of the adjustment, is limited. When the riflescope has a relatively large click value, the amount of elevation change in one rotation is greater thereby enabling the shooter to quickly adjust the scope for different distances.
Some riflescope adjustment mechanisms include a stop feature that allows the user to selectively set a position beyond which the adjustment dial cannot be rotated in one direction. This creates a stop point corresponding to a “zero” setting for the adjustment dial. Such a feature is shown in my prior U.S. Pat. No. 6,643,970, issued Nov. 11, 2003. Once set, this type of stop feature does not allow the adjustment dial to be rotated beyond the preselected “zero” point to a “negative” range. Others have created locking adjustment dials that can be rotated in either direction only when the user disengages a locking mechanism. Examples are shown in U.S. Patent Application Publication Nos. 2011/0100152, published May 5, 2011, and 2009/0205461, published Aug. 20, 2009, both assigned to Leupold & Stevens, Inc. of Beaverton, Ore. These lock at every selected adjustment position and do not provide a mechanical stop or non-visual indication when the adjustment dial reaches the “zero” position.
What is needed is a riflescope with an adjustment assembly that allows the shooter to return to the zero setting easier than conventional adjustments, even by feel, without visual confirmation of the settings. Moreover, what is needed is such an adjustment assembly that locks in the preselected zero setting, but which allows the user to adjust the dial, upon manually disengaging the lock, beyond that point into a “negative” elevation range or that locks in the preselected zero windage setting, but which allows the user to adjust the dial either left or right of the center windage setting.